Conservation Biology Overview

Conservation Biology

• Conservation biology is the integrated study of ecology, evolutionary biology, physiology, molecular biology, and genetics to sustain biological diversity at all levels.

Learning Outcomes

• Predict population fate based on size, genetic diversity, and inbreeding depression.
• Suggest conservation strategies for declining populations.
• Calculate effective population size, and recommend strategies to park managers.
• Justify "no intervention" policies in national parks using ecological principles.
• Classify conservation strategies based on the level of diversity targeted.
• Justify biodiversity conservation importance.
• Identify species at risk based on population ecology criteria.
• Describe human impact on ecosystem communities.
• Explain how species may not adapt to climate change.

Extinction Vortex

• Small populations (bottlenecks) are prone to extinction due to inbreeding and genetic drift.
• Inbreeding depression reduces fitness.
• Reduced genetic variability hinders adaptation to environmental changes.
• This creates a positive feedback loop, further reducing population size.

Effective Population Size (Ne)

• Ne represents the size of an idealized randomly mating population with the same level of heterozygosity as the population of interest.
• Heterozygosity is the fraction of individuals in a population that are heterozygous for a particular locus.
• Ne = N (actual population size) if the population has a balanced sex ratio, all individuals contribute equally to the next generation and simultaneous birth of each new generation, and the population size remains constant over time.
• Often Ne is less than N, reducing heterozygosity and genetic diversity.

Minimum Viable Population (MVP)

• MVP is the smallest population size where a population can sustain number and survive.
• It considers factors like Ne, individual range, mortality rate, and reproductive age.

Human Impact on Biodiversity

• Habitat loss: Changes in habitat (fragmentation, conversion to agriculture or urban areas) affect species dispersal and adaptability.
• Invasive species: Introduced species disrupt communities, increase competition, predation, or parasitism
• Overharvesting: Extensive exploitation prevents population recovery.
• Pollution: Excessive nitrogen and phosphate release causes algal blooms and oxygen depletion in aquatic ecosystems.
• Acid precipitation: Sulphur oxides react with water to form sulfuric acid, decreasing pH in lakes, impacting fish populations.
• Biomagnification: The concentration of toxins increases across trophic levels.
• Global warming: CO2 emissions increase average global temperature. Species unable to disperse, adapt, or have low genetic variation are at higher risk.

Biodiversity and Conservation Status

• Genetic diversity: Diversity within and between populations; loss limits adaptability.
• Species diversity: Variety of species in an ecosystem or biosphere; loss can be local (extirpation) or global (extinction).
• Ecosystem diversity: Variety of ecosystems; alterations can cause species loss and disrupt ecological functions.
• Status categories: Collapsed, critically endangered, endangered.

Why Protect Biodiversity

• Humans rely on biodiversity and natural resources for food, fuel, fiber, medicine, building materials, spices, and decorative items.
• Biological communities provide essential services like water purification, pollutant breakdown, soil formation, climate regulation, disaster recovery, and crop pollination.
• Ecosystem functions depend on the integrity of natural communities.
• Biodiversity is a complex evolutionary heritage—a strong moral obligation.

Biodiversity Hotspots

• Biodiversity hotspots are relatively small areas with many endemic and endangered species.
• Large proportions of plant, bird, and mammal species are concentrated in small areas.
• Protecting hotspots is crucial due to the high concentration of species.

Conservation Initiatives

• Captive breeding programs establish genetically diverse populations for reintroduction into the wild.
• International collaboration on potato and root crops enhances access to nutritious food in developing countries.

Habitat Conservation

• Strategies shift from protecting species to entire ecosystems.
• Fragmentation reduces species diversity.
• Corridors connect habitat patches for species movement.
• Large protected areas maintain ecosystem integrity and biodiversity.

"No Intervention" Policy

• Natural disturbances like floods and fires are often allowed to occur naturally.
• Many species depend on periodic disturbances for germination or growth.

Conservation Status Assessments

• IUCN (International Union for Conservation of Nature) and COSEWIC (Committee on the Status of Endangered Wildlife in Canada) assess species conservation status.
• Criteria include population size, distribution, threats, and life history traits.
• Ongoing assessments help track and evaluate species conservation risks.